I have the Thinkpad 385ED, I think it's virtually the same spec as the 380.
The CS4236B works as a Soundblaster 2 and/or Soundblaster Pro without any drivers in Dos (in windows you can use the proper Crystal drivers) - you can use the Thinkpad tools to set the resource configuration9 (eg 220/7/1) and run the Crystal software to initialise the chip, it doesn't need any drivers loaded or tsr's running.
So, yes, it plays Dos games quite nicely. Although you don't get stereo fm - only opl2 compatible.
All the drivers are fully available from IBM/Lenovo, right down to the PCMCIA (which I'm using for a PCMCIA fast ethernet card and MTCP, and also for a Roland SCP-55 midi card in games [it has a Dos driver and appears as a standard SC/GM device at 0x330]) and Infrared drivers for Dos.
One thing though, the DSTN screen is very slow compared to a modern TFT, so fps/high speed games like Doom can get quite blurry.
Mine is running 80Mb of ram (16mb onboard + 64mb sodimm) and a 160gb drive - I needed Ontrack to access it as the Thinkpad only supports a few smaller fixed sizes of disk.
My collection database and technical wiki:
https://www.target-earth.net