RD-300SX key hammers in RD-300NX

I recently came into possession of a used RD-300NX, which was missing its upper most B key (B7), both hammer and cap. I was able to find a fitting cap, but have been having difficulty finding a fitting hammer. Recently it seems that Syntaur has gotten RD-300SX (not NX) key hammers in their inventory. These look close, but not quite, like the hammers in the NX.

I was wondering if, despite the differences in appearance and labeling, if the SX hammers are compatible in the NX, and, if so, what kind of SX hammer is equivalent to the one I need. The NX hammer would have label “4L” on its metal “head,” and “1-2” on the metal part of the “arm”. I’m afraid I don’t know (or know where to find out) the exact part number.

Alternatively, if anyone’s seen RD-300NX key hammers being sold elsewhere online, or if they know Syntaur’s going to have them in stock soon, pointers/references would be great.

Finding parts for the Roland Rd-300NX is very hard. I just sold one to Keyboard Kountry. They might have some keys for sale, if you’re still looking.