The GPSDO I ordered from Amazon just arrived. The PCB is marked 2021-06-10, and looks exactly like the pics posted earlier. The same CTS OCXO and unmarked GPS. Yes, I took it apart before turning it on.
Now that I have a better look at the PCB, I can see that the LCD connector is actually labled "ISP-LCD". It is indeed connected to the SPI pins on the nearby ATmega 328p. So, in addition to programming the 328p, the uC is controlling the optional LCD via four digital I/O's (the other two pins are Vcc and Gnd).
Upon power up, it takes less than a minute to get a fix. The serial port uses a straight-through cable, at 9600, n, 8, 1.
u-center identifies the GPS as an M8030, 32 channels, with firmware 3.01 in ROM. I can't tell if there is any flash without trying to upgrade the firmware or taking the lid off the GPS (not going to happen). I believe v3.01 is the last version firmware, so there is no need to look for flash. I doubt that uBlox is going to release a newer firmware for M8 chips at this point. So, it's not a real uBlox GPS, but uses a uBlox M8030 chip. I don't think this is the Timing version GPS. The v3.01 firmware supports all of the current GNNS systems.
Looking at the config in u-center, only GPS is enabled (good for a GPSDO). NAV5 is set to Stationary, Auto 2D/3D. SBAS is set to Disabled. TP (timepulse) has a cable delay of 820 ns (I'll have to see if this corresponds to the length of the coax on the included antenna). TMODE is Disabled (probably best to set this to Survey-in for hours, once placed in its permanent location). The other settings look to be standard defaults.
Next, I tried Lady Heather. LH auto identified the GPSDO as standard NMEA. LH had a squashed display, but pressing F11 made it go full screen. The picture was taken after about half an hour since power on for the second time (first time was with u-center). I've never used LH before, so I'll have to read the docs to see what the graph means, and why it dings at me occasionally.
So far, so good. Next, I'll hook it up to my 11-digit frequency counter and see how it tracks with my HP 58540A GPSDO that has been running for about 2.5 years, since I moved.
Edit: I forgot to mention that the GPS is spitting out only NMEA sentences, no ubx. Of course, this can be changed in u-center.