Spare tire, GTS or Formula-S

I have been told that all 340 and 383 cars came with 5.5 inch rims The original spare is still in the trunk of my 340 swinger is 5.5 inch and sticks up. Unfortunately I threw the original rims out 25 yrs ago and am looking for another set.I was also told that cars with the trailer towing pkg also had the 5.5 inch rims. Steve