Hello Todd and welcome. Toggletop gave you a short and sweet version.
There are three varieties of the byf 41 with respect to the acceptance marks. The most common has two E/655 marks, then two E/135 marks and finally a mixed bag E/655 and E/135. Some have estimated that there are about 4000 byf 41 Lugers that are not of the two E/655 variety. So you can judge the rariety yourself. It is a very desirable Luger to own. Your pistol was very likely made in January of 1942 with a left over 1941 receiver.
As far as price goes, you did just fine.
As far as shooting it, you will run the risk of breaking a numbered piece and then the value will drop to a shooter grade and you could lose some bucks. It is your Luger, so the choice is up to you.