If you are picking an ATG team then Gilchrist wouldn't get a show based on keeping ability alone. By Gilchrist's own admission other keepers were his superior, especially Healy.
However, the equation for the wicket-keeper is 'Keeping + Batting', not just the singular task of keeping. Therefore, Gilchrist is the obvious choice keeper for any ATG cricket team. This is because Gilchrist placed the 'most importance' on his glovework and by any measure his skills would surfice for most ATG XIs.
Having said that, I think that when it comes to Test matches Alan Knott's 'Keeping + Batting' is slighting greater than Gilchrist's 'Keeping + Batting'. Obviously, Knott couldn't take an attack apart like Gilchrist. However, against quality pace like Lillee and Thomo, and Holding and Roberts he was a genius, and I can't imagine Gilchrist doing much better.
Note: Knott's batting average after the 74-75 Ashes series was 36.4 with 3 x 50s and a century. The only other English batsman to average higher were John Edrich (43.3, 2 x 50s, zero 100s) and Tony Grieg (40.5, 3 x 50s, 1 x 100s).