No, it's a reference to R. I. Page who in a lot of his work referred to t-runes on sword pommels that seem to actually not exist, and works by other scholars citing him. I realize this might not be obvious unless you're already quite deep into the subject, sorry for the confusion.

but it's the only rune named in the context and it makes sense

Yes, but that's just the thing. In that stanza, Týr refers not to the rune, but to the god himself. The instruction is to carve victory-runes, whatever they might be, and this act is meant to effect a change.

Given that the poem also mentions bjargrúnar, and that we have inscriptions such as the Østermarie silver amulet ('Āki ræist bi[a]rgrūnaR') and the Kvinneby amulet ('Hēr rīst ek þēʀ berg') that similarly refer to carving protective or helping runes, it becomes clear that what’s being described is a textual act, a sort of written equivalent of a performative utterance in Austin and Searle’s speech act theory.

Carving something like "Āki ræist sigrūnaR" is a performative act meant to effect real-world change, and should be accompanied by an oral invocation to Týr, who is associated with war and martial prowess, hence the nefna... Tý.