I may be way off base with this comment but here goes. Correct me if i’m wrong.
Dan S’ buckles use shoulderless spring bars because the spring bar holes go all the way through the buckle side wall. The OP’s buckle’s spring bar has shoulders implying that the buckle side wall has no holes.
This no-hole buckle is typical of knock offs commonly seen on sites such as AliExpress, the Chinese shopping site and home to all kinds of fakes.
For this reason and those stated above I am dubious of the authenticity of the OP’s buckle’s spring bar.
FWIW