With that comp release it'll be a 795, 797, or Super 797. Those are the only direct drive models in that series with the DSP valve. Should have some numbers stamped into the bottom of the block.
Assuming no parts have been swapped around (happens a lot with large frame Macs).............it
should be a Super 797 with the all yeller paint scheme (no black). A 795 or 'regular' 797 will have a black tank top and AF cover.
$10 for it and the Holiday eh? You did well. I'll quintuple yer money (and cover shipping) and you can keep the Holiday.