That's a very good question, checking ...
I'd hazard to guess that most of the "bush" is 1:63,360 usgs quad scale.
(AK 15', the lower 48 15' ones I have are 1:62,500 & treasured, check the asterisk, crying shame in my hiking book). Table at the bottom
They are bar none the best walking/ paddling paper maps ever made, anywhere, if you know how to fold, use and protect them in the field, where's my Silva ..
May I suggest that If you think you have 1:24k "urban AK" or 1:63k scaled usgs topo maps on the 60 that you go to the Map page > Menu > Map Setup> (scroll to the bottom), Scale > Ratio.
If you check the 1: __ k displayed in the lower right corner of the screen you may
be able to discern the scale by using the Measure Distance tool on the 60 with a little math.