Good luck on your quest. I have an EGO SBT that is in some ways much like a Ljutic w/the release being a 'button' in front of the trigger guard. It is well enough made, but I have never been able to find out anything specific about the company or who may have brought that particular model into the states or when.
Looking at the pics you've posted, it appears the bbl's. lump is brazed to a pair of forged bbls. Nothing wrong w/that, just saying. Also, that there may be some galling on the action's nose [can't really tell from the pics] & there could be an issue from that. I would test the bbls. for being on face at a minimum and if there is galling present, regardless of whether on face and discount the amount paid accordingly. If found to be off-face, I'd stay away from purchase at any price. Too, I would have a good look at the locks since it is obvious someone has been inside the gun. In summary, it is not a high grade gun & was likely moderately priced when made, in spite of some desirable features like the ejectors & hand detachable locks. Hard to judge Spanish guns from that time period on name alone. Another example of it being utility grade would be looking at the close-up pic of the bbl's. marking; they were struck, but w/o much attention to them being intended to take any high polish. Some Spanish guns of that era are sound work horses while others have had issues. The locks should tell you, assuming gun is on-face. Oh, and drop the firing pins w/a hard block of something against the standing breech, take a look at the noses for wear &/or breakage. They should protrude approx. 1mm for sound firing. Perhaps something of use for you here.
As an aside, Gough Thomas had a lot to say about Spanish guns in some of his works from that time period & it is, IMHO, as unbiased as you will find. You would likely find it enjoyable & informative reading.
