Most have some. Then you can determine what kind of mounts you need. One piece can be purchased to accommodate droop. The two piece you have to screw around with shims that slip/shift and having your scopes zeroed at close to the extended adjustments of the scopes. Both suck.
The only two ring set up without a base I like are the Burris Signature Airguns with the stop pin and inserts to adjust for elevation and windage. The also never damage a scope. They are a total no brainer for your HW50S and you can get them at Midway. They come with 11mm and 3/8" setups. They come in a medium which is fairly low profile and would accommodate a larger scope if you decide to change.
You may think the HW50 does not have much recoil but they can be just enough to need some extra stability of a one piece if you don't go with the Signatures. If all you want to do is plink then just throw some 2 piece rings on and shim them. If you want to target shoot then you have to think about what you are getting.
Here are the medium Signature Airgun rings. You need to get the inserts too. These will also fit any powder burner and are always in very high demand used.
These are inexpensive 4 screw low airgun rings by B-Square
These 11mm B-Square are solid medium 4
these Leupolds are very low profile although listed as medium 11mm
This RWS Lockdown fits 11mm and is VERY solid for an HW50 and has built in moderate droop compensation.
Just find out which of these 2 piece have stop pins.