My guess? Heavy.
I hated them combos - I was the kid on the lighter end, but still, they made them like tanks. Never dropped one, never necked one, but I did knee a knob once. The knob was ok, I needed a bandage - through corduroy pants, that Maggie "Mediterranean" got my knee good.
Ever carry a jonboat with some water in it? Lift up your end, and the other end gets heavy for the other guy?
That's my analogy for carrying one of these B****rds down a set of stairs. Suddenly, everyone has water in their end of the boat. to make matters worse, all the homes here were built in the early part of the century, with little thought as to how narrow one could design a set of stairs.
Congrats on the find....