Just had my copy of WD through the door with the 30k custodes rules, lots of interesting differences.
1. Standard profile is the same as the 40k one (not the sergeant) except that the attacks and Ld values are at -1
2. Detachment - use standard allied Detachment with one exception - you may count any unit of your choice as an HQ slot instead of its normal battlefield role.
3. Grenades, 30k custodes have plasma and kraks
4. No Deepstrike on 30k version and no transport options basically makes them unusable at present.
5. 30k custodes are bulky
6. The power knife is not a thing in 30k, also the spear profile is weaker than the 40k version
Str: as user/+1 ap: 3/2 (using the second value when charging).
7. The shields give a 4+ inv with a reroll if the bearer is in cc.
8. Two separate units, one with guardian spears (troops), the other with sword & board (elite), both unit size is 3-9, there is no sergeant analogue for either unit
- in effect this means that the banner is technically unusable at present, but might suggest that the boxed set has been designed with a mind towards making the spear unit, the sword unit, or a command squad which we presently don't have the rules for. The single cloak probably infers this as well since neither squad that has rules (custodian guard - spears, or sentinel guard - sword/shield) has the option for a sergeant.