Lemon Squeezer safeties? All 1911s have grip safeties (unless the have been purposely omitted or pinned and those are few and far between) and they are not "Lemon Squeezer" while I've seen that term applied to a couple of other designs, the difference in pressure needed to over come a 1911 grip safety and a "Lemon Squeezer" handguns (which were revolvers) or a "Squeeze Cocker" which is the HKP7 and it's variants is very, very different.
Maybe you're thinking of beavertail safety?
As to the Rock Island guns, as far as the low budget 1911s they aren't bad and have a good following. They used to have a satin nickel "tactical" model that I was thinking of getting for a while, but I had other fish to fry.
In the under $600 ball park they're a pretty safe bet.