Yes, this is an extremely rare module; I have seen only two in fifteen years, and only one was working (this showed up in a Date2).
You didn't mention if your module was working, but, even if it was, being set up for installation in a (time-only) P2, (I see no indication that the Date reed switch was installed), you would not have seen the functional difference that sets it apart from all the other 300-series modules. As an aside, I have never seen a 3010, 3011, or 3012 module; I don't think they ever existed, save as engineering prototypes...the standard 3013 module number designates "module 301, version 3". What is different on the 3050 is in the Date display. In the 3013, the Date is displayed for as long as the Date button is depressed...be it half a second, or an hour. In the 3050, the Date is shown for 1.25 seconds, then extinguishes, even if the button stays depressed. In simpler terms, the 3050 displays the Date in exactly the same way that it does the Time (and, in exactly the same way it's done on all P4 modules). I guess it could be considered a functional upgrade to the P2/Date and P3 models, and might have become the new "standard" P3 module, had the P3 remained in full production, but, by that time, the P4 models were being introduced, and the manufacture of P3 modules was reduced accordingly. It's just a guess, but I'd venture to say that only a single, limited run of these were done (perhaps a thousand, probably less); they are encountered far less frequently than, say, 406 modules (the production of which certainly did not exceed 10000...more like 5-8K, based on serial numbers).
Since the display programming is integral to the clock chip, it's almost certain that the chip package will carry a different part number than the usual 3013 module (RCA 82151) or 201-2 P2 module (RCA 81209). I can't read the number on your module (it might be readable in direct sunlight); I'll try to find mine and see if that guess is correct.
Final note: there is an even rarer version of the P2 circuit board where the little rectangular "block" transistors are replaced by bare transistor chips, directly wire-bonded to the circuit board and encapsulated in little round blobs of black epoxy (I have one of those, too, somewhere...). And, it is a fact that NOT ALL Time Computer clock chips were made by RCA; a fair number of P3s (and possibly P2s) carry chips made by Hughes.
Oh, and please don't ask me why there isn't a 302, 303, or 304 module...I have absolutely no idea...