PL/sql trigger code !!

We have some vendor based code in PL/SQL where instead of :old and :new the qualifications of columns is done using numbers i.e
:1.Datekey , :2.Acctkey and so on .

Is this an accepted way of referencing columns in trigger code ?

Oracle ver. 9.2.0.6


Rgds.,

:)

most people use old and new, but if you use numbers so be it, you can use whatever you like