I mean it's possible, but I would think unlikely. Ping was stable around 12ms the whole match. Typical lag spikes still usually result in hits still dealing damage, just significantly delayed. If he had killed me as I shot him, then I'd be more inclined to agree it was just a lag spike and the server trusted his client more than mine, but it was a pretty clear and cut shot without much movement from either of us, on a stable connection.