Looking at the age of the data, no. This relation was added in 2016 with an explicit OOC source. The original OHM server (and project) fell apart around 2015/2016, so there wouldn’t have been an OHM server to add the data to at that point.
Something was restored in 2017 but missing much of the original data.
There absolutely is an argument that something that was valid between 1838 and 1840 would make more sense in OHM now, but that would need:
- Someone to move the relevant data from OSM to OHM
- Some to update the data consumers of the currently-in-OSM data
Previous discussions with OHM people with regard to (1) have only resulted in “the person who added the data to OSM is free to move it if they wish”. See this other thread (among others). Personally, I’d have thought that the people behind OHM would be keen to see well-sourced and dated information such as the relation here in OHM, but there has been no offer of assistance to do that.
With regard to (2) I suspect that includes at least this site. I don’t know about others.
One final caveat with regard to the Irish situation - the mapping of “old” boundaries was in part inspired by the legal status that they still have today (a point someone made in one of the Irish chat channels a couple of days ago), so it’s not a valid assumption to say that “something with a start date of 1838 obviously has no relevance in the present day”; you’d need to check with the local community to make sure. Even if it does, it might still make more sense to be in OHM (given that the current iteration of that supports start and end dates explicitly), but that will require effort from both the people behind OHM and current data consumers - it won’t happen by magic.