I asked a couple of years ago; no one got back to me.
There are two types/runs of these items to consider:
1) OEM kit bits from the respective games. Unobtainium, and CAVE nerds that need to complete a kit, would likely pay at least half the going rate on a complete kit…if not more. STG fans are a special breed.
2) CAVE matsuri reprints of the kit bits, sold and given away at festivals and game shops throughout the mid-oughts. Not as desirable; a cubic zerconia to a kit’s diamond. Was offered $50 shipped a piece for each of these years ago over PM-ymmv.