Allen, no worries, altering the id is easy work. The top area of the sca file will look something like this example:
;Library000000
LibID( 92271076 55730816 D0000000 FC000001 )
LibObj( PWR 0
SIZE 16
SCALE 0.0019600000
TYPE 1281
NAME "WEP_DB_170gal_drop_gp" )
At the bottom of the sca file you'll see a reiteration of the item with its complete LibID. Because i'm using a "bundled" weapons bgl as an example (which probably isn't your case), you see a summary breakdown below of all the individual items contained in the bgl bundle. The WEP_DB_170gal_drop_g drop tank is the first item. Just slightly alter the values in any one or all of the four id columns, e.g., changing from ;92271076 55730816 D0000000 FC000001 << to >> ;92271088 55730888 D0000088 FC000088 or whatever you like. Note that all i did was change the last two digits. Something that simple can make all the difference.
Finally, the values in the bottom summary must match those of the LibID line of the top section. What makes this effective in achieving your aim is the fact that of all the items in your entire weapons library, these randomly selected numbers are now unique only to this item. Hard to believe i know, but entirely true. I always make a change in all four columns to ensure exclusivity.
************************************************************************
;library_min = 5573081692271076
;library_max = 5573081692271076
;id1 id2 id3 id4 PWR SIZE SCALE TYPE NAME
;----------------------------------------------------------------------------------------------------------------------------------
;92271076 55730816 D0000000 FC000001 0 16 33436735 1281 WEP_DB_170gal_drop_gp
;92271076 55730816 C0000000 F0000000 0 16 33436735 1281 WEP_DB_f4u1a_hook
;92271076 55730816 C0000000 F0000001 0 16 33436735 1281 WEP_DB_Brewster_rack_L
;92271076 55730816 C0000000 F0000002 0 16 33436735 1281 WEP_DB_Brewster_rack_M
;92271076 55730816 C0000000 F0000027 0 16 33436735 1281 WEP_DB_F4u1c_Cannon_a
;92271076 55730816 C0000000 F0000028 0 16 33436735 1281 WEP_DB_F4u1c_Cannon_b
;92271076 55730816 C0000000 F0000013 0 16 33436735 1281 WEP_DB_f4u1d_rocket_pylons_la
;92271076 55730816 C0000000 F0000014 0 16 33436735 1281 WEP_DB_f4u1d_rocket_pylons_ra
;92271076 55730816 C0000000 F0000015 0 16 33436735 1281 WEP_DB_f4u1d_rocket_pylons_lb
;92271076 55730816 C0000000 F0000016 0 16 33436735 1281 WEP_DB_f4u1d_rocket_pylons_rb
;92271076 55730816 C0000000 F0000021 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_a
;92271076 55730816 C0000000 F0000023 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_sway_braces_a
;92271076 55730816 C0000000 F0000025 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_covered_a
;92271076 55730816 D0000000 FC000002 0 16 33436735 1281 WEP_DB_154gal_drop_gp_a
;92271076 55730816 C0000000 F0000022 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_b
;92271076 55730816 C0000000 F0000024 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_sway_braces_b
;92271076 55730816 C0000000 F0000026 0 16 33436735 1281 WEP_DB_f4u1d_wing_pylon_covered_b
;92271076 55730816 D0000000 FC000003 0 16 33436735 1281 WEP_DB_154gal_drop_gp_b
;92271076 55730816 D0000000 FC000004 0 16 33436735 1281 WEP_DB_154gal_napalm_a
;92271076 55730816 D0000000 FC000005 0 16 33436735 1281 WEP_DB_154gal_napalm_b
I'm showing this Dbolt weapons package as an example because i did some alterations a while back to allow for a few more color varieties in this weapons bundle (wanted black pylons and tanks for my black Korean war night fighters). I would repaint the textures, rename them, then implant their new names into the bgl via scasm, replacing the old *.bmp names. Having done this, i had to give all the items new dp names and ID values and finally save the bgl under a new name. This obviously is not your project type, but the same ID methods still apply.