I have similar thoughts, it really seems rather like overkill. Either an old device or not a purpose-built tracker. Very large, and holy cow is that a TQFP-144? I've built local-storage trackers before with DIP-8 chips. I've not implemented GSM, but I'd be pretty surprised if a modern GPS+GSM tracker required this much horsepower.
Not to mention the board layout is pretty good, and because the GPS & GSM are integrated the layout engineer probably had to know a thing or two about routing antennas- while as you point out the solder job is quite amateur.
That appears to be a TQFP-120, and there aren't that many MCUs available in that package; I'm almost willing to bet it's a Renesas/Fujitsu part.
GPS + GSM modules are available (now - maybe not when this thing was designed) which would shrink the whole tracker down to one module, a few voltage regulators and related passives, and a battery:
Not to mention the board layout is pretty good, and because the GPS & GSM are integrated the layout engineer probably had to know a thing or two about routing antennas- while as you point out the solder job is quite amateur.