(1) There should be a set of numbers on the barrel, probably visible to the eye on the stock line but, if not, then in the barrel channel, (meaning, take the action out of the stock to see it). They'll be something like 234.34 which in this example means the 234th rifle proofed at the proof house at Vienna in 1934. There's your year. The 7x64 was first chambered in the M.1924 so that's the earliest date. They continued to be made in this calibre as long as they made Mannlicher-Schoenauers of this same design, until about the early 1970's from memory.

If it's a M.1924 it should say so on the front receiver ring - probably under the scope mount :-) The first model after the war was the M.1950. I've owned a M.1950 in 7x64. The checkering was also worn off. It had only a wing safety and no side safety, which by the time of the M.1952 had been rectified for American market tastes.

2)If your Mannlicher says on the front ring that it is a Mannlicher-Schoenauer, and it's not just a full-stocked Mauser copy that looks like one, then it would only say "Made in Germany" after the German-Austrian Anschluss when German troops entered Austria. It continued to be stamped "Made in Germany" until 1945. Perhaps a few still marked this way were also made up with parts afterwards until things got moving again in the early 1950's. Because the Steyr works was busy making armaments in 1938-45, there aren't very many "Made in Germany" Mannlicher sporting rifles at all.

I sold that particular Mannlicher, which I regret, but I still use the 7x64 cartridge and swear by it.