Most seats on the many AS 737-800/900s that I fly regularly certainly do recline. Right in front of the exit rows, and the last row (back of coach) they don't. As posted upthread, not specific to AS.
I'd say that the seats don't recline tremendously, but enough to make a difference.
At least as important as the recline, IMHO, are seat width and pitch. I just got off an AS 737-900 an hour ago and as I settled into my seat I marveled once again (as I always do) that there's very reasonable leg room in these coach seats. Soooooo much more comfortable than any of the major legacy US airlines I've flown on the past few years. In fact, I think Alaska's coach seats are perfectly fine, even for long flights. I've done a few trips to/from the Hawaiian islands, and even a crazy mileage run from SEA to FLL and straight back to SEA after a 10 minute turnaround. I'm a bit of a snob about seat comfort (or so my wife tells me) - I've become quite spoiled by nice business class seats on Asian airlines for very long flights - but I have no complaints about Alaska's coach seats even for flights across the USA or to Hawaii.
BTW, I think seatguru's language "may have limited recline" is their generic phrase for any seat that doesn't recline as much as others on that plane do - in other words, that covers seats that don't recline at all.
Avoid the seats in front of the exit rows, and the last row in the back, and you should be fine.