Wooden prostheses are a common repair intervention in conservation engineering of historic timber structures. This research explores the use of dynamic identification and acoustic testing for evaluating the structural integrity of historic timber specimens repaired with glued wooden prostheses. Replacing deteriorated parts in a wooden structural element with a new piece of wood of similar dimensions and characteristics favors the compatibility between the historic and new material, and allows to repair the element without having to replace it entirely. Minimizing the extent of the repair allows keeping as much original material as possible, which is interesting for protecting the authenticity and heritage values of historic wooden structures, especially when their surfaces are also decorated. However, on-site quality control of glued wooden prostheses is currently challenging, as existing methodologies for monitoring the quality of glued joints have been developed for factory settings, such as in glued-laminated timber production, making them difficult to use for on-site assessment in historic buildings. This paper presents preliminary results of non-destructive testing carried out on the beams of a 16th century wooden floor of coniferous species in a Spanish palace that were repaired with glued wooden prostheses. Ambient dynamic identification testing was used to compare the dynamic properties of a repaired beam with those undamaged. Afterward, sonic pulse velocity testing was conducted across the glued interface between new and existing timber to detect potential deficiencies in the adhesive plane that might have influenced the connection integrity and the dynamic properties of the beam. The test results provide insights into the effectiveness of non-destructive methods for evaluating the quality of glued wooden prostheses, advancing practical approaches for assessing repairs on heritage wooden structures.