535 vs M5 clutch master cylinder

[DanH]

Can I interchangeably use either of these master cylinders on my 92 535iM?

535i part# 21521155425, D=19,05MM
M5 part# 21522226477, D=19,05MM

They have the same bore size so what is the difference?
Is there more travel on the M5 one for the bigger bore on the M5 slave?
It seems the pedal should make either travel the same if it the attachment arm length does not change.

Also, is the master cylinder push rod supposed to feel like it disconnected internally at the other end when I have the master out of the car?

Thanks

[shogun]

I have checked in the dealer catalog (not the online version on the net), Both have D=19.05mm. Both numbers are valid and there is no mention of interchangability.
FCP Groton sells the Febi cheap,
21521155425
BMW Clutch Master Cylinder - Febi Bilstein 21521155425 | FCP Euro (http://www.fcpeuro.com/products/bmw-clutch-master-cylinder-bilstein-21521155425)
Part number: 21 52 2 226 477
Supplement D=19,05MM Important! Limited storage life. Please Observe expiry date on parts label. Exception: Painting material, see Painting manual "BMW Group Original Color System"
Usage
5' E34:
M5 (S38)
M5 3.6 (S38)
M5 3.8 (S38)

Here cheap for $109, dealer price 160 BMW Clutch Master Cylinder 21522226477 - RM European Auto Parts (http://www.rmeuropean.com/Part-Number/Clutch-Master-Cylinder-__21522226477_FTE_10902E0B.aspx)

[shogun]

I have checked in the dealer catalog (not the online version on the net), Both have D=19.05mm. Both numbers are valid and there is no mention of interchangability.
FCP Groton sells the Febi cheap,
21521155425
BMW Clutch Master Cylinder - Febi Bilstein 21521155425 | FCP Euro (http://www.fcpeuro.com/products/bmw-clutch-master-cylinder-bilstein-21521155425)
Part number: 21 52 2 226 477
Supplement D=19,05MM Important! Limited storage life. Please Observe expiry date on parts label. Exception: Painting material, see Painting manual "BMW Group Original Color System"
Usage
5' E34:
M5 (S38)
M5 3.6 (S38)
M5 3.8 (S38)

Here cheap for $109, dealer price 160 BMW Clutch Master Cylinder 21522226477 - RM European Auto Parts (http://www.rmeuropean.com/Part-Number/Clutch-Master-Cylinder-__21522226477_FTE_10902E0B.aspx)