I would recommend using low height rings for an 870 with the Konus AimPro 1.5-5x32mm Rifle Scope. Typically on shotguns, you want the lowest height possible. And since the objective lens on this scope is relatively small, you would be able to utilize low height rings.
No, this does not include rings. If you need assistance in finding a set, contact us at techsales@opticsplanet.com.
The eye relief is indeed 2.9 Inches. Using a picatinny rail and picatinny rings, there really is a lot of flexibility in being able to move the scope to adjust it to the right spot once you get it mounted up. The picatinny rail below gives you almost 5.5" of rail to use for your picatinny rings, allowing you to move those rings to the front or back to get that scope in the right position.
https://www.opticsplanet.com/egw-remington-shotgun-picatinny-rail-scope-mount-2074.html
Konus states it has a mounting length of 4.9".