Ironically, my 35/f2 seems to be the same variant as my 50/1.4. It's a Non-Ai version with a rubber focus ring. I Ai'd it myself, also. It's all part of my "Original, Black Nikon F" bag, with a factory Ai'd 85/1.8 and an untouched, pristine 200/f4. (Whoops.... I forgot about the 24/2.8.)
These threads are persuading me to just let go. Use my D700 like my old FM, F & Nikkormats, & shoot like I did 20 years ago & not be so boxed in by the worry of sensor dirt & the meanderings of "handle with care," "digital worry nonsense."