2 hours ago, texasz said:

Should I be concerned about this?

I don't think so, once it's all buttoned up it's a closed system, the way it was it had a reservoir above where the brake line attached.   However, Wilwood MC's don't have a great reputation, there are a couple of guys here on the forum that have had to replace them more than once.  

This below is a cut and paste from the product description on Wilwood's site. With 50/50 output, I'd think front rear line switch wouldn't matter as long as the other systems to reduce the rear braking are maintained. I could be wrong. I put tubes in people's throats for a living so hopefully experts step up...

 

Wilwood’s Remote Tandem master cylinders provide one of the safest ways to actuate four wheel or dual caliper axle brake systems. The cylinder features 50/50 output from a 1.00" bore with 1.10" stroke. This master cylinder can be bolted directly to Wilwood's single mount pedals. The kit is shipped complete with the master cylinder, pre-installed 4 ounce reservoirs and 3.38" x 5/16-24 pushrod.