That thing has a PS/2 port. The port was designed in 1987 and became obsolet when USB (1997) was introduced. It has a lot of multimedia keys. They became common in later half of the 90s. Your keyboard was likely produced sometime between 1995 and 2000.
It's probably a rubberdome. You can easy check that by levering a key cap out. They are only clammed in and can be pushed back in again.