Here's what I wrote when I first posted about this back in 2010:
It’s possible this is more than just a throwaway line of dialogue. When it first aired on CBS from 1992 to 1993, The Young Indiana Jones Chronicles (as it was originally called) alternated episodes set during two different periods of young Indy’s life; Indy as a teen (played by Flanery), and a pre-teen boy (played by Corey Carrier). This could be a reference to an episode that was planned for the pre-teen Indy at some point in the future. Unfortunately, the series did not last that long.
This Houdini reference appeared in the excellent episode "Daredevils of the Desert" and was released on DVD as part of The Adventures of Young Indiana Jones Vol 2: The War Years.
I love Indiana Jones and I'm hoping to see the part recast and more adventures in the future. Maybe even one that shows us what happened in Australia when Indy met Harry!