Should be fine to carry on IMO, your levels posted thus far aren't too far off the ball. Below KH 7 and Ca 350 you may get immediate issues, but ATM, your just looking at slower growth... You'll have all you need within 2 weeks for testing and supplementing, a single hard coral in a tank the size you have listed will not drop the levels into the danger zone in that time, especially if you have a good water change regiem. If you have more hard corals that I don't know about though, it may well be an idea to hold off the delivery.
All the best
Rabbut