Yep, that definitely will be a rubber dome as it's very, very similar to the original one I bought back in the 1990s and still have. If you look closely, the num/caps/scroll lock area has 4 tabs holding in the plastic that covers the indicators. On mine that's quite wobbly and generally so are the keys. But the feel is quite nice and the woobliness goes away once you have your hands in position on the key (like resting on home row.)
Neat find for sure!
