Here are the revisions:
HARDWARE 1 "Xenon":
-90nm CPU
-90nm GPU
-NO HDMI
-single GPU heatsink
-Uses 16.5A on 12V rail, comes with 203W power brick
HARDWARE 2 "Zephyr"
-90nm CPU
-90nm GPU
-Has an HDMI port
-Extended GPU heatsink with heatpipe
-Uses 16.5A on the 12V rail, comes with 203W power brick
HARDWARE 3 "Falcon"
-65nm CPU
-90nm GPU
-Has an HDMI port
-Extended GPU heatsink with heatpipe
-Uses 14.2A on the 12V rail, comes with a 175W power brick
HARDWARE 4 "Jasper" (brand new, appears in consoles made on/after November 2008)
-65nm CPU
-65nm GPU
-Has an HDMI port
-Has extended GPU heatsink with heatpipe
-Uses 12.1A on the 12V rail, may come with a 175W or 150W power brick
The consoles most prone to the Red Ring of Death are the original 2 (Xenon and Zephyr) because the 90nm CPU and GPU combined make a ton of heat that can damage the connections between the board and the chip. The Falcon improves the failure rate dramatically, but the 90nm GPU is still present. The Falcons are still prone to Red Ring of Death errors because the GPU heat can break the connections under the chip. The Jasper boards are the best, as the 65nm chips produce much less heat than their 90nm counterparts. My new Jasper console barely puts out any noticeable heat, while my old Xenon can significantly heat up a cold room during gaming sessions.
Judging by the MFR date on your console, it is most likely a Falcon, though if you're lucky it could be a Jasper. The Jaspers first appeared in Arcade packages, so you may have one. Check your amp rating on the back of your console. Also, if your console has 256MB internal memory (and didn't come with a memory unit), then it is definitely a Jasper.
As for your old Pro, selling it won't get you a whole lot of money, the thing is doomed. It may just be freezing now, but freezing is just days away from a full blown red ring of death. The best thing to do is sell it to someone who knows how to fix it, you won't get anywhere near the price of a working used console, but you can get some cash for it and give it a second chance (my friend gave me his old 360 and I managed to fix it, been using it for a year but finally decided to get a new one, got a Jasper on Sunday and just in time, the old one is having issues again).