I have a 350mm F5.6 Zeiss Tele-Tessar C I got years ago for 600 Euros. Multicoating makes no difference with this lens, just make sure to shade it.
It is my favorite long tele on my 500C/M's and 500EL/M's. I toted it to rock concerts for tight handheld closeups for several years. The 350mm and the 40mm Distagon make a great pair for me. The 350mm is handholdable at fastest speeds, unlike the 500 Tele-Tessar.
It all fit in an incognito Domke Messenger bag.