Hi there,
Do you have sample of Daniel Williams' signature in 1868 and in 1869? I am not advocating you purchase either document, but if you can access the church register for the 1869 marriage, you should be able to view his signature on that document. The NSW BDM marriage record will likely have scant info and could well be all in the handwriting of the clergy or the clergy's clerk, but the actual church register should be extant, and if so, should have the actual signatures for the bride and the groom ....

If so, then it may be sensible to consider buying the 1868 d.c. where the informant's signature ought to be recorded and then compare. WILLIAMS was and still is one of the more popular surnames in regional NSW. TEN males aged at least 21 years are listed by that surname in the Orange Electorate in 1870, and that's back when it was not compulsory to enrol to vote. Only SEVEN listed under JONES in that same roll.

None for a Daniel Williams in 1870 Orange Roll.
BUT
1878 NSW ER ORANGE
Daniel WILLIAMS, residence, Orange

Grevilles PO Directory 1875 Cadia
Daniel WILLIAMS, miner, Burntyards.
(the locality is Burnt Yardshttp://wikiedit.org/Australia/burnt-yards/7004298 )
GREVILLE P.O. Directory 1875 CARCOAR
all with surname WILLIAMS
Dionysius, labourer
Henry, miner, Burntyards
William, miner, Burntyards
Daniel, miner, Burntyards
I do NOT believe there were two by given name of Daniel. I suspect it is a duplication in the 1875 directory, Burnt Yards is still in the same location as it was back in the 1870s.
JM