There is NO "generic" shower valve trim. ( But there are aftermarket, brand specific items available.). You MUST get trim made for your EXACT brand AND model.
Now, Moen is one of the most widely found brands. You must specify if yours is a pull-out type or just a turn-type. Moen themselves, and many aftermarket companies make trim for your valve, including in the bronze. Take your parts to a good plumbing supply and they will have what you need,