Here’s the 05 stamp. Which I don’t know if is correct for the 280sl.
Please find enclosed a handful of info about camshafts in our cars. 05 is there, it is a late US camshaft. Us camshafts were less "sharp" then Euro (Emission control regulations). Do not worry too much about the number on the casting. They were not changed with every modification. The fact it starts with 114 does not mean it was not used in W113. There are at least two part numbers for the US camshafts for 280SL, both starting with 114 (not your casting number though).
You are getting advise on possible source of noise already.
I am not a mechanic, I can only say that ticking may also be heard if the clearances are wrong (you have to adjust them in these engines - has your mechanic done that, and, done correctly?), when cam lobes or rockers or lash caps wear is excessive or when you screw down the valve cover too tight - its supports bent and start touching rockers.
The geometry and oiling issues, as waltklatt is spotting, are, however, priority to check in my opinion.