No 1......ask us something harder, like......when were the guns actually fitted.
Too late....the answer is between Nov 40 and Feb 41
Actually the best clue is to look her up in the museum and go through the years.
A couple of interesting links if you don't already have them
http://www.bismarck-class.dk/tirpitz...ittingout.html
http://www.bismarck-class.dk/tirpitz...tirconstr.html