Dana - just thought I'd pipe in as well. While I agree with everything others have mentioned, I'm going to double up on what Gerry Ide mentions "I'd look it over well before jumping for it". Seeing that non-standard speed control lever (Gerry calls shift lever) is a big concern to me. I would have some suspicion of the linkage being modified. Not that it wouldn't work, but how well and how correctly does it operate?
With regard to the PTO lever missing (on the left side), I also see the turn-buckle linkage for it is missing on the right side, and the front lever with button is also missing. This engine uses an integrated starter instead of the Starter/Generator used on a 149, and I suspect the location of the integrated starter conflicts with the turn buckle so the entire PTO linkage and assembly had to be removed in order for this engine to be used.
I copied and enlarged one of the pics and it certainly looks like the electric PTO has been removed as well. You'll probably see the crankshaft sticking out of the engine about 3".
I also see the air duct on the front of the engine which was not used on a 149 but the muffler box that would attach with it is gone and the original style 149 muffler is installed. The air duct probably conflicts with the basket pulley used for the Starter/Generator belt. So this would be another thing you'd have to change in order to use the manual PTO if you want to go back to 149 style. Others suggest going forward to the electric PTO but if it's not there at all this could get a little expensive.
I see you're in Colorado and we don't have many members there, and I suspect not many IH Cub Cadets. There are used parts readily available in the Midwest and East Coast areas, so you'd have to pay shipping for anything.
It might be sorta minor, but the hood appears to be pushed down lower than the front of the dash housing. I suspect the hood support bracket that bolts there has been removed and is missing.
Not trying to scare you off here. This tractor could be a good snow pusher (recommend at least a pad on that seat pan). But bringing the PTO back to life could take quite a bit. Also, you'll need a set of chains for those rear tires to push snow. Turf tread tires would be better as well than the AGs on it now for snow.
And one more thing, the 149 would have a Kohler Model K321A 14hp engine. There should be a decal tag on the left side of the flywheel shroud on this engine just below where the choke and throttle cables are mounted, and right where the frame curves down and narrows. If this is a 14hp engine it will show Model K321AQS on the tag. If you can't see a tag and/or model number it could be anything from a 10hp (K241AQS), 12hp (K301AQS), or even possible a 16hp (K341AQS).