What do you mean by 'true'?
There are a number of royal regiments in the British Army. See www.answers.com/topic/list-of-british-army-regiments-1994.
King's Own Royal Border Regiment, The Blues and the Royals, Royal Armoured Corps, Royal Corps of Engineers, Royal Regiment of Artillery, The Royal Gurkha Regiment, are some that come to mind.

The Royal Regiment of Artillery has an emblem with the Crown on top, then an artillery piece, the motto at base.

Outside of Britain-
Royal Regiment of Australian Artillery
Royal Regiment of Canadian Artillery
etc., etc.

I believe all regiments called Royal have 'letters patent' (right term?).