The Marshall 2045 is a 2x12" cabinet originally intended for lead, bass or organ applications. This cabinet was part of the Marshall catalogue between years 1972 and 1976. These cabinets were originally loaded with Rola Celestion G12H 55Hz 16-ohm (T1281) speakers rated at 30 watts each, wired in parallel, resulting in a 8-ohm total load. I, however, originally bought this cabinet without speakers. Later on I luckily found a pair of Celestion Greenback G12H T1217's from 1972 with rare and desirable Pulsonic cones and installed them into the cabinet and they sound phenomenal.
I'm not 100% certain of the year of manufacture, but since there is a similar cabinet in the AmpArchives website with the serial number 54703 confirmed as a '74 and mine is just 173 numbers off, I would guess mine is a '74 as well. Feel free to prove me wrong.
s/n: 54876