Keith O - I agree with Jeff, the sticker in your pic is the standard HP rating sticker that Kohler put on the tin cover over the head. I believe it was used on all the AQS version engines at least those in Cub Cadets. I always loved to see the statement "Kohler Cast Iron Line". You should have 2 decals nearly appearing as one on the left side of the engine on the side of the flywheel shroud. The top sticker will be the Serial No., and the larger sticker will have the Model and Spec number and other Kohler details. It's often difficult to see and will be located down at the same level as the frame. Hopefully it's not torn off. Also, I see you are missing the rubber grommet that should be surrounding the spark plug. They are still available and very cheap. It seals the hole in the tin cover where the spark plug fits, so the air flows across the head and provides the intended cooling. Without the grommet the air flows up around the spark plug and not fully across the head. It's actually 1 item I look for to know that someone has taken pains and good care of their tractor. Doesn't mean you didn't get a good 1650, just something I like to see on them.
Also, did I miss something? I see messages discussing that you may have the front hydraulic outlets but I don't see any pics. Maybe they are confusing your profile pic with the tractor you just picked up, or am I confused and you are talking about the tractor in your profile pic?
Bill J - hey thanks for posting a pic of your patent decal. Looks like there must be a ton of different ones used on the QL series. Sure makes a 100% correct restoration very difficult.
That 122 looks pretty typical. They are certainly 1 tough tractor, and the Creeper makes it a little bit tougher.
Ryan Mc - I'm not really trying to burst your bubble, but there is a reason those units are rare. Still nice to have because of the rarity but you should be aware of why.