Two C16 Grades - what's the difference?

[Gizzydash]

Picked up two differently marked C16 timbers from local builders merchant, who informed me they'd both cut the mustard in terms of being used as structural timber in a floor i.e. building control would be happy. Markings on each are attached, one with a lot more detail and the other just a red C16 stamp.
Are these both of the same quality/standard, and if not what's the difference?

Thanks

 

[^woody^]

C16 is a standard. If it is marked c16 it meets the standard.

 

[Gizzydash]

Fair enough

 

[John D v2.0]

I would personally try to keep it consistent in case they start with different moisture contents or they are planed to a different thickness. But if you've got them already and checked, it's probably not an issue.