If skipMagic is enabled do not set the magic or size on the block, the values would have been incorrect.

lib/block.js

@@ -114,10 +114,6 @@ Block._fromBufferReader = function _fromBufferReader(br, options) {
     info.size = br.readUInt32LE();
   }
   info.header = BlockHeader.fromBufferReader(br);
-  if (options.skipMagic) {
-    info.magicnum = 0;
-    info.size = info.header.bits;
-  }
   var transactions = br.readVarintNum();
   info.transactions = [];
   for (var i = 0; i < transactions; i++) {