Could be XP-L HD as well. It should have visible bonding wires but with this photo quality they may be missing.
In general, here:
is a great collection of LED photos that help identification.
Anyway, XP-L HD is slightly less efficient and slightly narrower than LH351D.
Everything I wrote comparing LH351D to SST-20 applies to XP-L HD as well, but to lesser extent.