This makes me blue!

This bottle/vase appears to be a fairly early piece of studio art glass and is about 5.5" high x 4" in diameter and weighs 1.25 lbs. The pontil is a bit unusual. There are some marks etched on the bottom which appear to be initials and a year (L O 73) and maybe a catalog or inventory number (4 73 - 42). The latter could be "April 1973, 42nd piece made in that month". Maybe the work of an actual studio art glass artist, not a student. The "inventory" number could also be part of an inventory system shared by several artists in a studio, hence the relatively large number, 42, or maybe that is not too much for a single studio glass artist to produce in a month.

All guesses on my part as to what these numbers and letters are and may have meant. Also, note the line in the middle of both number 7s. That is not commonly done in the U.S., so this could be a European piece.

I think the year 1973 was still fairly early in the Studio Art Glass Movement, which started about 1962 in the U.S., and which might help to identify the artist or studio as there were a relatively small number of artists in the Studio Art Glass movement at this time. I'm not sure how widely the movement had spread by 1973, but it is a potential research opportunity. I picked this up from a seller in Kansas, which might also be a clue. Input on any of my assumptions welcome.