Nice slags. German Slags only come in a few colors. Shades vary within those colors. German striped Transparents and opaques come in a myriad of different color combos.
You have mostly 2005 JABO Classics in your pic. Yes classics can most definitely be identified by when they were run. Part of the fun is properly identifying them and sorting them into their runs.
The marble had to have a starting snip/cut and a stopping snip/cut. All machine made marbles are going to have 2 seams where the glass gets sheared off. It’s not like only patch structure marbles have 2 seams…they are just more obvious where they are.