I have seen that silver gun handle before on another title but I can't remember what it was but I remember it being a proto game around the same time.
I would like to see some photos of all the games serial numbers and study the under Playfield and the front facing playfield edge for stickers and ink stamps. You can learn a lot that way.
Your game should have a playfield number/batch code on it.
This we'll tell you how early the playfield number is.
You have to study every inch of the machine and every inch under the playfield to unlock the secrets.
If u can post all the photos.
I have 3 x Last Action Hero machines I can compare all the numbers and stamps to if u like.
I enjoy all the Scherlock Holmes part of working out what these pinballs are.
The stamps n stickers hidden unlock the production secrets which is fun to find and work out.