A search of Munster and shamrock reveals the answer in John’s fantastic post here...
https://www.britishbadgeforum.com/fo...25&postcount=3
Shamrock backing introduced Feb 1915 on SD cap. Newsom photo is dated Aug 1914. I’d imagine Rickard photo is similarly prior to Feb 1915 given he was KIA in May 1915.
Re the ‘ORs badge’ you do see die stamped bronzed badges with blade fixings. They are somewhat of a quandary, discussed here...
https://www.britishbadgeforum.com/fo...Munster+bronze