There's a thread on RDF where someone is having the same issue. The Stalker XLR is recorded in the stats but the HiFi announces it as "speed-sensitive laser". It appears to be an issue with the HiFi module, or the CPU firmware isn't sending the correct gun ID to the HiFi.

That said, the Bluetooth module/app reports the Stalker XLR correctly, as I tried it on my tester when I was testing with FatLazyDog last week.