Marantz 240 amp

Question for the group. I am considering purchase of a Marantz 240 amp with the serial number prefix 240b-and number 3317 (240b-3317)  I haven t been able to find any information on the number other than none of the ones I saw had the 250b-xxxx. 
The other thing is the front plate appears to have a etched brushed label, rather than on the face.
I am wondering if anyone could shed some light on this mystery?


There is the service manual. Serial number is just that, a serial #.

Looks like a 240b # 3317 of the production line.. Just so you know it wasn’t uncommon for manufactures to start at something other than # 1 and lots of them left out #13,  or some weird duck, would snag it.. :-)

Thanks for your response. I was thinking maybe a test run of some sort. Btw That weird duck wudda been me! 
Funny there are those out there.. I try not to tempt the "gremlin factor"
No 666, no 13, 1313, or 131313. :-)