My MGM dry-type transformers have their manufacturing date stenciled into the name plate.
BTW, there is a steady business by those purchasing just such units.
Salinger is always in the market.
I'm constantly getting solicitations in the mail for such gear.
When you say MINT CONDITION I take that to mean that it's never been installed.
In such a case, it would be deemed New Old Stock -- and could be sold on eBay PDQ.
You'd need to get much more specific since no-one makes 79.5 kVA transformers. NEMA has set sizes -- which just so happen to be detailed in Ugly's tables.
The nearest (NEMA) size would be 75 kVA.
It's also essential that you specify whether it's 3-phase DELTA or STAR on the primary side... and DELTA or STAR on the secondary side.
By far the most common transform is Delta to Star: 480 to 208Y120.
Other essential metrics: its temperature rating, its weather rating 1, 2, 3R, etc.
Also the taps on the primary and secondary. These are normally listed right on the name plate as plus/minus voltages.
It's also essential to know whether it's copper or aluminum. It's Z, or impedance is also important.
If the unit has been in service its value plunges -- as the bidding assumption is that it's a cripple/ or in some way uneconomic.
Good luck.
