The fiber cores are different diameters for OM1 fiber (62.5 microns) versus OM3 (50 microns). Thus, you can experience additional signal loss (versus what would be calculated with a single fiber type) and uncertainties within the mixed fiber link; not to mention the potential confusion for future technicians troubleshooting the link.
Below is a link which explains some findings when mixing different diameter MMF cores, based upon the transmitter types.
http://www.thefoa.org/tech/fib62-50.htm
It will be difficult to say if your links with operate with the mixed fibers (too many variables). It would generally not be a recommended or a supported configuration by most vendors, especially for a permanent, production link.
Hope this helps!
