There was a website that had a 100% full detail strip and reassembly (in fact I am the one who posted it here - years ago) however the website has been taken down as of about 3 years ago and I have never been able to find it again.
There might be a printed "shop"manual" but if there is I am unaware of it. I have also not been able to find a S&W Armorers Manual for the M41 and am not even sure if one can be gotten. The M41 is a tough gun to get info on - that's for sure.
I am certainly not a professional Gunsmith and am 100% self taught. Pretty much every gun I have dived into, I have figured out piece by piece on my own by just using mechanical ability and common sense. Most of it is just mechanical ability, familiarity with firearms in general and good ole' common sense and yes, some are tougher and more complicated than others. I will admit that some are a royal pain in the butt - but once you do figure it out, you will never forget.
I have gone farther into disassembly of the M41 than just the standard Field Strip, however I have not quite done a 100% full disassembly due to the fact that I have not yet needed to. If that day ever comes I will do it but again I own this gun since 1979, shot it often and have net needed to do so. Unless you have a specific reason to replace an internal spring or part, the M41 is better left intact for anything much beyond the Field Strip.
Exception: Replacement of the Extractor is a common repair or service and only involves removing a pin - an easy task that is outlined by available instructions posted online.