Yes, the blog post confirms this -
If you invested in our crowdfunding round last year (in March 2016) you’ll automatically be eligible to invest again this time if you’d like. You’ll still need to pre-register and pledge the amount you’d like to invest, but you won’t enter the random ballot. On March 14th, we’ll email you with full details on how to complete your investment through Crowdcube.
Since there is a cap on the amount that existing investors can invest (£1,000), they will not be able to use up the total 2.5m set aside for Crowdcube investors.