Mini14 Question

I have a Mini14 that was made in 1976. I have noticed that the rear sight ap and the slide lock differ greatly from the more recent models. It came with a Butler Creek folding stock, but the gun wouldn't cycle. Turns out that the stock didn't mate up with the gas port worth a flip. Butler told me that their stock are for series 181 and leter. Has anybody else ever experienced a problem like this? I'm having a hard time locating a stock for my series 180.:target:

 

Thanks for reminding me about the Saxet Gun Show. I forgot that it is all ready the first weekend of the month. Guess you figured out where I live too!