Link g++ 3.3 libs with g++ 3.2 binary?

[Derekasaurus Rex]

I have a C++ product that consists of application code and quite a few
OSS libraries. Until recently everything was compiled using g++
3.3.2-1 (henceforth 3.3). Unfortunately this compiler is not the
standard version on my target Linux platform (CentOS 3.9) which uses
the slightly older gcc-3.2.3-59 (henceforth 3.2) in its standard
toolchain.

The decision to use a non-standard version of GCC was a foolish one
and I want to revert our project to g++ 3.2, the standard version for
our CentOS 3.9 platform.

Naturally it would be ideal if I could rebuild every line of code with
g++ 3.2 for a completely clean re-compile. However, for reasons beyond
the scope of this post, there is some risk and complexity associated
with this, and rebuilding every third-party OSS library with g++ 3.2
is not trivial.

Would it be completely foolish to switch compilers and build all of my
application code with g++ 3.2 while continuing to link with OSS
libraries built with 3.3? Does g++ offer sufficient binary
compatibility within the 3.x tree? Or is the only responsible path to
rebuild all of my code, including third-party libraries, with the same
compiler, namely 3.2?

Of course I plan to eventually rebuild everything with 3.2, but I'm
trying to understand if this can be done in stages (i.e., application
code first, then third-party libraries).

Any input appreciated. Thanks.