The physical MagSafe adapter remains unchanged from a pinout perspective (the shape has altered externally from a T shape to an L shape and back again) for almost every Macbook except the 2012 Macbook Air and Retina Macbook which use MagSafe 2; Adapters are available to connect a MagSafe power supply to these machines, but you cannot use a MagSafe 2 adapter to power anything other than the 2012 Air and Retina at present.
You need to ensure that you use the correct power rated charger for the Macbooks. Macbook Airs use a 45 watt supply, through to something like 85 watts for Macbook Pros.
It's OK to use a higher rated supply than is required, the charger only supplies what is asked of it, so a Macbook Air on a Pros power supply will only request its 45 watts, not get fried with 85 watts.
Conversely, it's not OK to do the opposite, running a MBP on an Airs power supply will request up to 85 watts of draw on a 45 watt power supply, and burn out the adapter eventually.