They are two different colours - LA7U is Pearl Gery, and LP7V is Atlas Grey.
Pearl Grey is nicer (but I'm biased

)
Pearly Grey was used predominantly on the runout models from '91 onwards and early Mk3s. I've never seen a Pearl Grey car as early as 1988.
Side-by-side I think Atlas Grey has more of a bluish tint, whereas Pearl Grey is more yellow, though there isn't a great deal of difference between them.
If you are unsure of the colour, maybe VW could help to identify it off the Reg no/chassis number?