Use Google Analytics in AMP HTML

google-analytics.amp.html

<amp-pixel src="https://ssl.google-analytics.com/collect?v=1&amp;tid=UA-12345678-1&amp;t=pageview&amp;cid=$RANDOM&amp;dt=$TITLE&amp;dl=$CANONICAL_URL&amp;z=$RANDOM"></amp-pixel>

/*
 * Required parameters:
 * v = API version number (currently 1)
 * tid = Google Analytics property identifier (UA-12345678-1)
 * t = hit type
 * cid = client id (you should implement this via cookie etc.)
 * z = random string to bypass caching (amphtml generates this to $RANDOM variable)
 *
 * Some nice to have parameters:
 * dt = document title ($TITLE)
 * dl = document location ($CANONICAL_URL)
 *
 * References:
 * https://github.com/ampproject/amphtml/blob/master/builtins/amp-pixel.md
 * https://developers.google.com/analytics/devguides/collection/protocol/v1/reference
 */

Do you need to add $ before the variables? ref: https://github.com/ampproject/amphtml/blob/master/spec/amp-var-substitutions.md, linked from https://github.com/ampproject/amphtml/blob/master/builtins/amp-pixel.md

I guess this is superseded by this now? https://developers.google.com/analytics/devguides/collection/amp-analytics/