You will need to check the literature.  I believe that IRC Section 754 adjustments that result from IRC Section 734(b) (i.e., property distributions or partnership retirements/buybacks) are entity level "step-ups" potentially applicable to all partners.  Whereas an IRC Section 754 adjustment under IRC Section 743(b) (i.e., for a sale or exchange between partners....and possibly an inheritance step-up...would need to look) is a partner level step-up.  Hence, only the entity level step-up would be included in the partnership's return and UBIA.  The partner level step-up under IRC Section 743(b) would need to be computed and reported separately, solely by the partner to whom it applies.  It appears that the 743(b) checkbox was designed for that purpose (see PS instructions).  Special allocation 'might' also get the asset into that partners UBIA on the Section 199A worksheet.  See that partners Statement A for 199A reporting.

Hope that helps.