no you didn't, you payed the base skin price, which is 1350
not to mention that was remanent of the old system, in which you could purchase new skin for less on the release, which was shutdown few months before it was officially stated it is retiring last year.
If you want to go into detail, not a problem.
First skin borders were introduced with bringing back legacy skin in 2013/2014. Players who purchased legacy skins in the past would receive a slight decoration border on their respective skins, in gratitude for their purchase and compensation.
Then in the september of 2015, project skin lineup was introduced. Because standard skin release was active at the time, it would mean you would buy them for 975 instead of 1350, with exception of Master Yi. So in a persuasive attempt to get players to buy skins for full price, they sweeted the deal with a shinny border on you skin, which is exclusive if you buy the skin in the first week of release and a promise that you will be able to buy the skins at the regular discount next week.
All in all, that was a fair trade off, and met with a positive feedback from the community since it was repeated next year with the second generation of project skins. From that point, skin borders become more common practice recurring with elementalist lux , dawnbringer riven and nightbringer yasuo. All those skins had borders you could acquire if you purchased skins on their release and they weren't charged extra.
Now, they are trying to push a price on skin borders. I am completely against this extra charge, since it's something we were already getting. You're buying skin at full price instead of waiting for a 50% discount. That's what border was for, getting you to buy it asap.
Now, if the community does pushback on the price raising (as it is), like we did when they tried to increase price on Surprise party fiddlesticks, it would be a signal that players are ok with this price increase, and as it goes, give something an inch it will take a mile, who knows what they'll come up with next. Price of keys for an example. I'd say it's quite a bargain actually, considering how much value i had received over the years. They might increase the price of them someday perhaps.