I'm a big fan of those El Paso Weaver scopes.
I have 2 K2.5's, a J 2.5, and a KV 6. All are installed on guns that I shoot.
I also bought a K 3 for six dollars,that is a little foggy. I'm going to send it to El Paso for a rehab and install a modern duplex reticle.
Your K 2.5 scope is marked to indicate the model,and that determines the date of manufacture. One of mine is a model 60B,and was made between 1956 and 1966.
Copy the data and send it to:
Weaver Scope Repair Service
1121 Larry Mahan Drive,Suite B
El Paso,Texas,79925
Phone# 915 593 1005
Frank