Sanity check with static routing between Aruba switches

Working on transitioning away from a flat network design and I need a quick sanity check to make sure that I'm understanding HP terminology correctly. I have two sites, connected via dark fiber that we own. Call them sites A and B.

Site A = 192.168.100.0/24 vlan 1

Site B = 10.100.0.0 /16 vlan 1

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There are more than just these two subnets, but these two are the only ones that matter. I have two Aruba 5406r switches acting as cores....one at each site. Both switches have IP routing enabled. Right now I have a /29 in between the two cores, call it vlan 20. Site A core has an IP of 10.1.1.1/29 - vlan 20, and site B has an IP of 10.1.1.2/29 - vlan 20.

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Core A has the following

ip route 10.100.0.0 255.255.0.0 10.1.1.2

Core B has the following

ip route 192.168.100.0 255.255.255.0 10.1.1.1

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Am I correct in my understanding that I should tag vlan 20 on the both ends of the point-to-point link between cores? Or should it be untagged on both ends because vlan 1 exists on both networks, thus stripping all the vlan tags once it reaches the other core?

Since vlan 1 exists on both networks with a different IP address range (I know), I can't just tag vlan 1 like I would a normal access switch--> core switch uplink. Hoping that someone can clear this up for me...haven't been able to find anything for this specific scenario on Google.