Why Motorola offers 2 different versions of O5 head?

First with dark grey plastic insert and O5 mark at the top right corner.
Second one is with light grey insert and XTL 5000 mark. Also came with round /\/\ logo at the left.
Both for Motorola XTL5000!
Why???
And few more specific questions for guru:
1. They are fully compatible?
2. Which one is newer?
3. First one came as part of kit HLN1471_ (O5 CTRL HD/CHIB REMOTE REPLACEMENT). But second one?