No, 220 is not correct. At 264 kts the hydraulic pressure will be removed from the extension/retraction system.
I could quote the AMM, but you can check the FCOM 1.32.10 P3
Sorry, but 220 is correct.
As I said, 260 is the speed for gear hyd pressurisation.
The green hydraulic system actuates all gear and doors. When the aircraft is flying faster than 260 kt, a safety valve automatically cuts off hydraulic supply to the landing gear system. Below 260 kt, the hydraulic supply remains cut off as long as the landing gear lever is up.
However, if you look at Fcom 3.1.20 (operational limitations)
Maximum speed at which the landing gear may be retracted (VLO retraction) 220 kt
So you should slow down to 220kts before retracting the gear.
I agree you could in theory retract below 260 as the system will have pressure though.