It looks like there is a bolt hole between 2 and 3 exhaust ports, but no bolt. I put a piece of wire down the hole and it seems to go all the way into the block. Should I put a bolt in there? Also, I did some research about the different heads and read about the production code stamped in to them between 2/3 intake, but my code doesn't look like any others. Also I don't know if it means anything, but like I said before, when I got the bike the electrical system was a mess, the wires to the stator were melted, so I had to replace the stator. When I pulled the cover off the oil galley plug was missing, I bought one on ebay and put it in, should I take it back out?
Thank you to everyone for all the help and info
Yes, put the oil port plug back in, with a new O-ring if you can find one. I might be able to come up with one, I'll look around.
The front bolt: if there are the threads in the cylinders to accept it, do put that in: it was added after the K0 to prevent oil leaks that come from crankcase pressures pushing against the thin zone of the head gasket at that point. Only the K0 engines omitted this bolt. If the head is K1-K3 and the cylinders are K0, there will be no hole nor threads in the cylinder's block to hold the bolt in.
About all the "mix" of parts: another possibility is an insurance-funded rebuild of a major crash of a bike. It was not uncommon for folks to fully insure these bikes in the day so that in the event of an accident it could be replaced, or fully rebuilt, at the owner's discretion. I personally aided (or did) several bikes of various kinds in my shop that underwent this activity. For example: if the bike were originally a K3 and the (fully-insured) rider got rear-ended by a car, the frame would have been toast and the chain, going slack from being hit while the rider may have been sitting at a stop with the bike in gear and the clutch pulled in, then doubled over and punched through the engine cases when the surprised rider let go of the clutch lever. So, the insurance would pay for a new or used frame installation and new cases on the engine. This sort of thing was very common then, and lucrative for shops like mine. When all was said and done, the insurance company would certify the bike to the State as an "insurance rebuild" bike and it would retain its original title albeit with the new frame number, regardless of that part's origin.