Here's what I've found thus far:
From the FBAR instructions (page 6):
Exceptions
Participants in and Beneficiaries of Tax-Qualified Retirement Plans.
A participant in or beneficiary of a retirement plan described in Internal
Revenue Code section 401(a), 403(a), or 403(b) is not required to report
a foreign financial account held by or on behalf of the retirement plan.
From 26 USC (*) 401(a)
(a) Requirements for qualification
A trust created or organized in the United States and forming part of a stock bonus, pension, or profit-sharing plan of an employer for the exclusive benefit of his employees or their beneficiaries shall constitute a qualified trust under this section—
(emphasis added)
From the first words, an element of doubt. As they say 'I've got no dog in this fight'. It's just extra typing on the FBAR form. I'll have already reported the pension (and additional information about it) on 8938.
http://www.law.cornell.edu/uscode/text/26/401