Nothing wrong with having a good tool as your first tool, so long as you take good care of it and respect what it can do both as a tool and as an implement for removing meat from fingertips. To begin with, I'd definitely hang on to it - you are really unlikely to find a better one cheaper.
Myself, I wouldn't go chopping the back off it yet - you may want to use the thing for stuff besides whittling foam. For instance, my late father was a boatbuilder, carpenter and general woodworker and he liked his Skil for doing long, mostly straight work. As I like my Rockwell/Porter Cable #653- it's a nice tool for removing a lot of stuff, fast. But there, the long planer shoe is a plus, not a minus.
Before you go and break out the hacksaw, use the planer a while as is. Maybe pick up a short Harbor Freight cheapie and compare 'em - it's not like you're doing twenty boards a day and that's all you do. As I mentioned, you may build a boat someday, or do post-and-beam work, or any one of a dozen other things where the longer shoe is an advantage. 'Cos you can't just stick it back on, y'know?
I am actually quite pleased to hear that you started with a Surform. Too many figure that the first thing you should have is a power tool like a planer, and myself, I completely disagree. Learning to use a hand tool, learning the 'strategies' for making a long, straight tool do what you want it to do on a curved surface, that leads directly to figuring out how to use this bigger, heavier tool well.
Lastly, many of the early Skils, like a lot of power tools of that era, came through with a nice, polished finish before standards dropped and they found they could make a painted tool cheaper. That one may have been prettied up ( I see what looks like a new cord on it, for instance) but it may well have come through with that finish.
hope that's of use
doc...
