I would say you could use most anything as long as it is RTK with the following observations.  I just had a parcel layed out by a pro surveyor.  They just assumed a base position anywhere BUT they went to dug up markers on roads and intersections to "bring it back to the real world" which then let them find the parcel area based on known reference points.

If you want to bring those points and/or lines between points into a mapping system then you can probably work with that just fine.  However if you want it to "register" with aerial imagery etc., then you need to set the base up to known cordinates rather than just assuming it.  I am not an expert at "post processing" assumed points but it can be done.  It would be easier to at least make sure the base is "sub meter" if you wish to register up with other data layers within reason.

I had the surveyor give me the lat, longs, of "legal" points that they converted to WGS84 and that I hope to load up someday and even use as an AB line to put up fences etc.  But really I could just go to the real world points on the ground and do the same thing to say "lay down a fence line".

If you just want to bring the points into a mapping (preferably a good GIS program) and do some measuring it probably won't matter a whole lot until you want to use other layers and then you have to be on the same "system" as the other layers of data.

After that it starts to get really involved and I guess that is why the surveyors get paid the big bucks.

Arnie