Yes, but it's all accent and inflection. Lewis has the most distinctive Gaidhlig accent to my ear - very Scandinavian sounding. They sound a little like the Swedish chef-like for me (only a little mind!). They tend to use vowels slightly differently too, for example the word 'bainne' (milk) is pronounced sort of like 'Bann-yae' here on the western mainland, but on Leodhais it is 'Bonn-ya'. That's a fairly simplistic example I guess (a linguist I ain't), but it is just like the differences between a Scouser, a Brummie and a Londoner speaking English - they can all understand each other but the accents and terminology can be tricky.
Also, south western Scottish speakers on Islay, Kintyre, Arran, and even Partick in Glasgow can understand Donegal Irish speakers to a fair degree provided that they A) take their time and B) use their dialect as much as possible without rigidly sticking to Standard Irish. I would imagine, but I'm sure there will be some exceptions, that a Scot given some time in an Irish Gaeltacht or an Irishman in the Scottish Gaidhealtachd would pick up the local dialect pretty quickly... in the same way perhaps that someone from New York would eventually figure out what a Geordie was on about.
I'm not sure if I'm explaining that very well, but hopefully you'll get the idea.