Yes and No!
If you intend to purchase an original style
`points` type pump then it is not important as we have recently made
steps to ensure that all 12 volt `points` pumps are dual polarity. This
means that whether you order positive or negative earth, you will
receive a replacement, dual polarity version.
If you are
ordering the later `pointless` type pump with the electronic switching
then it is still important to make sure you have selected the correct
polarity for your vehicle. This is because the circuit board used in
the production of these pumps is hard wired to either positive or
negative and can not be changed.
All electronic SU fuel pumps
have a suffix of either `EN` for `Electronic Negative`, or `EP` for
`Electronic Positive`. Unlike the standard `points` type fuel pumps,
the part numbers for these pumps do not contain a space between the
alpha and numeric codes.