If you get a picture of the blade or the inside of the scales you can ID the blade steel. The s30 blades have an "s" on them, the ats34 and bg42 blades are unmarked. If you can see the date markings that would help also, the change between steels is always going to be gradual, but if it is 2000 or earlier than you for sure have bg42 since the change to s30 happened in 01. You can also do a search for that specific graphic because some were only made during a certain time period.
If you post a picture here we might be also able to give you more information.