Stanford's Motets Op38

[Timtin]

I noticed in IMSLP's list of Stanford's works that Op51 just had a question mark against it. A quick check here
http://searchworks.stanford.edu/view/264300
suggests that his 3 Motets Op38 are in fact that work.
Checking C.F.Porte's book 'Sir Charles Stanford' shows Op38 as being the unpublished 'Queen of the Seas' Overture, whilst the 3 Motets aren't mentioned at all.
Therefore, is it possible that the 1905 Boosey and Hawkes attribution of Op38 to these 3 Motets is spurious, and should they perhaps being given the new title 3 Motets Op51 instead, as published by C.T.Wagner in the 1970s?
(Rightly or wrongly, I've already altered the Op51 entry in Stanford's list of works to flag up this anomaly.)