btw those maps are from valve.
All of the CS:S GG maps we play on the IBIS GG server are in GO. I've played city_advanced, Funtimes, Lego, etc. That said, they're poorly scaled and honestly, GO is pretty inferior to CS:S, at least in my opinion.
Yup, specifically remember playing Deagle. I also think I played texture_deagle as well. They're definitely out there, you just have to find a server with them in rotation. Again, they're not scaled well so they feel a little 'off' compared to their CS:S counterparts, but they easily beat the maps included in the game.