Unfortunately , the label says it all: "Made in China".
There are just tons of factories over there turning this stuff out, and it all looks the same.
There was a time when we had a large...but manageable number...of companies making faucets and shower valves in this country. They tended to make a certain model for many years before changing the design, so there were a lot of them around. Plumbers became familiar with them because you learned by 'seeing and doing'. And each brand was distinctive...as soon as you saw the handles, you knew what it was. Same for the internals....you knew by looking at it who made it.
That is all changed now. All the imports look alike, and they tend to copy a national brand in appearance. Internally, you have to find a distributor who may sell that brand and know the parts.
From the model number label on the side of the shower valve, it is consistent with being a number from Globe Union...glacier bay, seasons, pegasus, danze, gerber, etc. I would call that number and see it they recognize it.....1-888-328-2383