i have it in front of me right now, it says pr3...The b17 is only usdm,
92-93 gsr engines, they are very rare. maybe about 2000 made total, but they are exactly the same as the second gen b16 heads, with diffrent cams.

pr4's are b18a/early b18b heads,;later ones are p75

this is from what ive seen, not a chart, you cant always believe those charts

now for the prelude head, that ill have to go check out.