I would take a gravity reading and taste it!
it looks like it fermented well, did it come out of the top?
if you had the white cap on it then that is definitely OK. CO2 is heavier than air, so would have protected the beer, and your white cap would have stopped bigger bogies from getting in.
but all in the taste, right?
For the Top gauge this is your output pressure, adjusted by the screw
Numbers in red = PSI (marked bottom centre in red above the screws in the gauge)
Numbers in black = Kg/cm2 (marked bottom centre in black above the screws in the gauge) I think, picture not clear, but makes sense as 10Kg/cm2 = 142.233psi
so if you want 8psi it would be approx the first ...