Hi, the current safety standard for cots is AS2172:2003, however I have seen some cots which has AS/NZS 2172:2013. If I have a cot that is AS/NZS 2172:2003, would it still be ok? Thanks

Cot standards are reviewed regularly by ACCC - the date reflects the year the standard was reviewed - any cots with standard AS/NZS 2172 is current.
eg this page below from ACCC was posted in 2017.
https://www.productsafety.gov.au/standards/household-cots