Yes. The shell in BusyBox is derived from ash via dash. They have diverged over the years but there is some flow of patches between the two. While dash aims to be POSIX-compatible the BusyBox shell includes selected bash features.
The shell in the busybox-w32 port has much of the POSIX and bash goodness of upstream BusyBox. It's a native WIN32 application so there are some concepts that don't translate well. For example, job control isn't supported and signal handling is limited. On the whole, though, I think it provides a reasonably comfortable shell experience.