Only other marriage showing around that time/area is in Bala, Q1 1856, 11b 579
Robert Jones and Margaret Jones
This is probably the marriage in Llanycil parish (Bala) ~
26 January 1856
Robert Jones , 20, bach, labourer, Llangwm, David Jones, labourer
Margaret Jones, 19, sp, -, Bala, John Davies, Tailor
Witnessses - John Hughes, Ann Jones
From what you've said re ages, etc. this looks unlikely so the 1855 one, previously referenced, is the most likely.
Gadget