I'm trying to sort some parts for 1950 Pan. I have early covers (1/2" square nut underneath for screws) in two lengths, the shorter pieces being 3/8" less in overall length. I had assumed the short ones were 49 and 50 parts, the extra length added in 51. I don't see any part number suffix for the stainless covers to indicate a change in my oem books.Can anybody verify that? Any opinions offered would be appreciated.