Yes....except breeders usually list the quickest flowering time they've observed and that's likely only typical for one phenotype of that strain. If it's a pure indica, 60 days might be right on the money but even then it depends on how close to ideal your growing setup is. Back when I used T5s for lighting, flowering times were always a bit longer than they are with the LEDs I now use. If it's a hybrid or mostly sativa, you could be in for a 12-week flowering phase. Cutting the light cycle down to 11/13 or even 10/14 can encourage them to finish faster. I used a dawn-to-dusk timer that is programmed to know what time the sun rises and sets depending on the date. I lied to it and told it the date was September 21 when I made the change to 12/12. Two months later, all of the girls from five different strains finished at the same time but possibly at the cost of some productivity.