Xindak XA3250 - pcb

Well I spent the evening tube rolling on this preamp (NOT the 3200 model) and at the end of the night noticed that there are not actually markings outlining where the 12AT7 and 12AU7 tubes shoud be installed.

Some photos on the net appear to be using a different pcb than that which is contained in my chassis.

Are there any owners or experts out there who know whether the 12AX7 tubes should be at the front (ie closest to the front panel) or the back of the pcb?