That first L looks pretty good to me. 4,500 hours is high-ish, but there's lots with more hours than that still going strong. Sure, you might get problems, but at the price you're not that much out of pocket. I think your odds are reasonably good on it if you don't abuse it, and if it's running well when you buy it.
You might need a bigger machine, but that's more money. That L won't lose any value unless it breaks. Check if it's mechanically sound enough, if it is, buy it. Use it. If it does what you want, good. If it doesn't, sell it for most of what you paid, and you'll have info about what you want that's different.
I don't think an L is generally strong enough in the loader to lift large round bales. Particularly an older one (newer ones I think have stronger loaders). But you can get a 3ph bale spear, and it'd probably lift them fine on the rear.
