Quick brake question

[Steve Cole]

I am getting ready to put brake fluid in my brake system for the first time. The PO installed disk up front and kept drum in the back but never finished the install. I finished it and was about to put in fluid and bleed the system when I noticed the master cylinder has the same size reservoirs for both the disk portion and the drum portion. I am used to the disk reservoir being smaller than the drum reservoir. It does have a proportioning valve just below the MC. Is this setup going to be ok or do I need to replace the MC? I'll try to post a pic.