Jaguar - Xj6 :: 1994 - Very Slight Leak From Gasket On Newly Replaced Water Pump?

Recently, I bought a new-to-me 1994 Jaguar XJ6 which had a small laundry list of things that needed work. Amongst them was to have the waterpump and belt replaced. Long story short, after getting it back from the shop (I'm a repeat customer) and 50 miles down the road, I checked things out under the hood. I saw that there was a small bit of coolant sitting on top of the pump where the mating surfaces meet. It appeared that was some weeping from the gasket. I'm a little perplexed because this shop hasn't done wrong by me before, but there's a first time for everything. Is it possible that the cold weather in North Dakota (routinely -10) is a factor? It doesn't appear to be a catastrophic leak by any means, but I intend to keep my eye on in it. In the mean time, I made sure the bolts nearest the leak were adequately tight and put some red RTV sealant where it was leaking. Is it possible this problem will "go away" or do I have to try to shake down the shop and get them to re-check it/fix it? Frankly, I'd rather not have to deal with them again, but I paid them good money to get it fixed.