Hello

No you can't use with S7-300. In this FAQ you will find more inforation.

2. Requirements:
You can only use the FB TIMESTMP in configurations that support time forwarding and time stamping of binary signals. These are as follows:

CPUs:
CPU 4xx with CP443-5 for forwarding time messages (from 6GK7443-5DX02-0XE0)
or
CPU 4xx with forwarding of the time messages (e.g. CPU416-2 DP from firmware version 3.0)

Distributed I/Os:

Startup module IM153-2, supports redundancy with time stamping (from 6ES7153-2AA02 firmware version V1.2.3 (release 10))
or

IM153-2 FO, supports redundancy with built-in FOC interface (from 6ES7153-2AB01 from firmware version V1.2.3 (release 9))

Digital input SM321 (6ES7321-7BH00-0AB0) isolated 16 DE, DC 24V, process interrupt, diagnostics
or

Digital input SM321 (6ES7321-7TH00-0AB0) isolated 16 DE, DC 24V, NAMUR, supports diagnostics, with FOC functions

regards