Date code on a "K" frame

[Chris Haynes]

I found this rolling chassis sitting out in the weeds where it had been sitting for many years. It was an old desert racer minus the engine. The date code on the frame is 3R. Is this a KR frame? I have never seen the letter "R" used in a date code. Only A-L.

[bmh]

Sure it's a "R" and not a poorly stamped "B"? I,ve seen date codes on big twin frames that were not stamped very well.