Mcintosh MC250 ( Does this look like some of the caps have been replaced)??

Hi
Just purchased this and was wondering if the blue caps and the one GE one look like they have been replaced? See anything else??

Also that number stamped into the frame is that the serial number?

UPdate found the SN on the faceplate (see last pix)

SN is 59L31 any ideas on build date?

TIA

http://www.angelfire.com/il3/twins/www.mc250.html