That type of six lever was very popular before and for some time after the turn of the century, (the 19th to the 20th). In fact it was so popular that I believe every lock manufacturer made one or more versions. I say versions because companies like Eagle and Sargent and Corbin also made them with different names where the brand is shown on yours. A much more arre form has the same external appearance but is marked 8 lever.
There are collectors who try to get every brand of that lock they can find and the variations may actually be into three digits now. Typically they sell for $5 - $10 without a key and a little more with a key. Yours might bring a higher price than normal as I don’t recall seeing one with the Segal brand name and certainly not with a branded operating key.
BBE.
