Mixing DBLink versions

Hi All,

Due to some historical idiosyncracies in our environment, we have a custom 8.3.7 database installation built from source. We'd like to install dblink into this, however there are some problems with doing so:

1) the 8.3.7 database was built on a CentOS 4 build box that has since gone away
2) currently we have only 8.3.9 code built against CentOS 5
3) the GCC compiler on CentOS 4 was quite old
4) possible API changes in dblink between those versions

My question, how risky would it be to copy the dblink.so and .sql files from the CentOS 5 compilation of Postgres 8.3.9 over to the CentOS 4 compilation of Postgres 8.3.7? If runtime errors result, how severe would they be? I.e., would they take down a postgres backend or possibly the postmaster daemon?

Thanks,
David