In most cases I don't believe an alignment is necessary after shock replacement. While you are under there I'd also suggest checking/replacing the steering dampener. That's the shock that lays up next to the drag link, it bolts to the drag link and the frame. An excellent $30.00 investment.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.