The rounded Stratocaster neck should drop into a square ended Tele neck pocket provided that both guitars are from the same Fender series.
American Standard dimensions should match. MIM Standard series dimensions should match. MIJ series dimensions should match.
What will probably not match is Vintage Meets Modern, Indonesian Meets non-Indonesian, Chinese Meets non-Chinese, licensed third party meets genuine Fender.
A twenty one fret Stratocaster neck will leave two small gaps showing between the heel and the edge of the pickguard. A twenty two fret neck will mask the gaps beneath the fingerboard extension overhang.