[Mondial]

Its not unusual for the IF to be off that much. Over the years, several previous owners or servicemen may have tuned the IF by ear, not using an accurate signal generator. 

I have recently been working on a 1930's RME-69 receiver and could not get the crystal filter to work. Finally found the IF at 505 kc, not the correct 465. Realigning IF at 465 matched it up to the crystal freq and allowed it to work properly.

The mica compression trimmers in the IF of these radios have a lot of tuning range, so it is not difficult to align them way off freq.

The IF offset will also affect the dial calibration, so you will probably find, the dial off a similar amount. Setting to the correct IF freq should correct most if not all of any dial error.