Marzio, welcome to the Luger Forum. You haven't provided much needed information to make a firm appraisal.
But, these comments may be helpful. The byf 41 was used primarily by the Military (Army). If the serial number suffix, if there is one, is T, U, V, W, X, Y, Z or no suffix, the black plastic grips are proper. The suffix letter can be found on the front of the frame, below the barrel and just below the numeric portion of the serial number. Then the magazine should be an "fxo" type, milled steel body with either an aluminum or black plastic bottom. The serial number may or may not appear on the bottom (if aluminum)
It is important to be able to recognize original plastic grips. Also, some internal parts are stamped with the last two digits of the serial number.
If the suffix range is correct, the internal parts are matching, the grips are original and the finish is original and in excellent condition, and your price is in Euros, it is a reasonable purchase.
I hope this helps! Good Luck!
