I agree that it appears to be an '8', though I can't imagine why they chose that glyph.
But R681 should be a 680 Ω resistor (likely a 5% tolerance), not 681 Ω. A 681 Ω resistor (likely a 1%) should be marked 6810 (the leading 'R' is not significant). The last digit should always be the multiplier, though I have seen a very few resistors where the multiplier was left off if it was a zero, which makes no sense as it creates ambiguity.