Evening Andrew.
I have about four of these and from recollection two are earlier Mark 1s and there are 2 Mark 2s.
All have or had anti bear trap (I've removed a couple from memory) and none had or have safety catches. I have seen (a few years ago) what I took to be a late 335 with a safety. I had assumed like you that these were in effect a Mark 3 version. Clearly last of the line.
Your 335 is giving respectable ME there in .177. Indeed that wouldn't be too shabby in .22. They are lovely accurate guns- primarily I suspect due to their superb barrels and barrel locks. Funny how that concept never really took off? I think it's a good feature myself.
These are guns that deserve more respect than they get. Not a gun to try and wring power from as they can be easily over stretched. Always thought it was a bit of a bad marketing ploy to label the range with the "magnum" moniker at one stage of its production run.
Dave