1st (County Antrim) Battalion, Ulster Defence Regiment (1 UDR) was formed in 1970 as part of the 7 original battalions specified in The Ulster Defence Regiment Act 1969, which received Royal Assent on 18 December 1969 and was brought into force on 1 January 1970. It was amalgamated with the 9th Battalion, Ulster Defence Regiment in 1984 to form the 1st/9th Battalion, Ulster Defence Regiment.
The Ulster Defence Regiment currently has 9 battalions.
There's no information provided on how many battalions that the regiment currently has, so it must be neither definitely correct nor definitely incorrect. It probably got it wrong because it saw "7 original battalions" and figured there must only be 7.