Help identify American Standard shower valve

I'm trying to repair/replace a shower valve. It's an American Standard - I think from the early 70's.

Does anybody know what the part number could be to replace the cartridge? I really don't want to tear down the fiberglass tub to get to the rough-in. Any ideas?

Thanks in advance.

Try Alfano Plumbing Parts or NYRP Corp

If it is American Standard, the colors and design look right, but I have never seen one with a crucifix stem, it is an Aquarian. The 4 gpm model is #57864 and the 8 gpm version is #69382.

Thanks! Got a replacement cartridge. Will give it a shot tonight.