Yes, the historic Wolverhampton / Walsall boundary is along the Sneyd Brook, so just east of the M6. The historic Wolverhampton / Cannock boundary is along the current Cannock Chase district / South Staffordshire Actually boundary.
Pelsall, Featherstone and Brownhills are also within the lands granted to Lady Wulfruna and the historic parish, as is Arley. Yes, the place the Severn Valley Railway runs through.
The Boundary Commission report that led to the changes in 1966 literally says "we put Willenhall in with Walsall against all the principals just to make Wolverhampton smaller".