Is it the original title? If it isn't, the "2" could have been a typo. I was lucky enough to have my original title and registrations from '54 to '75 (I found them folded over under the seat), and some digits in the motor number and GVW were left out or changed from time to time when the registration was updated. It was the same person at a small tag office who renewed the registration each year, but I guess mistakes happen. Someone else may have a much better answer, but that's my guess.
The "4" that you mention seems like a valid number. From the way I understand, production numbers started at 1001 for that time period, so I don't think 356 would have been the entire production number.
