Help finding unit with FPN

[scarelettarms]

I recently found a Mauser HSc w/ holster that my grandfather had locked away in the basement. It is named to a Major Stockel FPN 31430.

If anyone can help me find the unit for this it would be very helpful

Thanks

[Ian Jewison]

FP Nr. 31430

(2.1.1940-27.4.1940) 9. Kompanie Grenzwacht-Regiment 51, cancelled and became Fp.Nr. 30212 B
(1.10.1940-27.2.1941) Stab Pionier-Bataillon 134,
(23.4.1944-24.11.1944) 15.9.1944 cancelled.

Major Kurt Stöckel. Kommandeur Pionier-Bataillon 134. 25.10.1943 awarded Deutsches Kreuz in Gold

/Ian