My understanding is that your memory is correct; The Irish Regiment did wear a solid kilt in a brown/mustard yellow shade known as saffron.
When I was in Borden circa 2000 my roommate was a piper in the Irish. There were two jokes extant at that time.
a) he was in the 2nd Battalion, The Irish Regiment of Canada - the joke being that there is no 1st Battalion, and
b) they had at that time an adjutant (from a Regular Force infantry regiment who shall remain nameless) who did not like the kilt, and therefore, he showed up at camp in green CF trousers and a green beret with the regimental cap badge as his headddress. Don't know of the veracity of that story, but I do know what he was wearing for a CF uniform. Either way, very odd for a piper to show up at camp without a kilt. Then again, it may have been a dodge to get out of the extra kit maintenance required of highland dress (I was not fond of the brass polishing, shoe maintenance, and combing of horse hair that accompanied my parade preparation - but did it out of regimental pride).
The Toronto Scottish wear a similar kilt, though in a much different shade, known as Hodden Grey.